A quantitative urban model for transport appraisal
本文为交通成本收益分析构建了空间一般均衡模型,以伦敦伊丽莎白线为例,发现其政策评估结论与部分均衡法接近,但能同时评估交通与土地利用政策并给出空间分布细节。
Transport cost-benefit analysis (CBA) has evolved since its inception to become one of the most influential and ubiquitous applications of microeconomic theory, shaping billions of dollars of investment in the infrastructure sector. A key limitation of transport appraisal practice is its reliance on partial equilibrium (PE) models, which limits the ability to quantify potentially transformative impacts outside the transport market. In this paper, we build upon the principles of quantitative spatial economics to design an empirically relevant appraisal method in spatial general equilibrium (SGE). Our model yields travel time valuations that are micro-founded through an explicit leisure-labour trade-off, making them unique to each residence-workplace pair. We decompose the aggregate welfare change in SGE into direct user benefits and wider economic impacts, and we quantify the statistical uncertainty surrounding each welfare component. These features allow us to compare the welfare estimates in SGE with those of the mainstream PE method. In the numerical implementation of the model, we replicate Greater London with 983 distinct spatial units and the introduction of the Elizabeth Line, a major urban rail project. We find that transport appraisal in SGE is unlikely to yield fundamentally different policy evaluation results compared with a correctly quantified PE CBA. However, the SGE approach (i) is well suited to assessing transport and land-use policies simultaneously, (ii) complements aggregate welfare estimates with a detailed spatial pattern of local economic outcomes, and (iii) integrates the causal estimation of key parameters into the modelling exercise.